Magnetic Nanocomposites of Coated Ferrites/MOF as Pesticide Adsorbents.

Magnetic metal-organic frameworks (MMOFs) are gaining increased attention as emerging adsorbents/water remediation agents. Herein, a facile development of novel MMOFs comprised of coated ferrite nanoparticles (MNPs) and UiO-66 metal-organic framework is reported. In specific, coated Co- and Zn-doped ferrite magnetic nanoparticles were synthesized as building block while the metal-organic framework was grown in the presence of MNPs via a semi-self-assembly approach. The utilization of coated MNPs facilitated the conjugation and stands as a novel strategy for fabricating MMOFs with increased stability and an explicit structure. MMOFs were isolated with 13-25 nm crystallites sizes, 244-332 m2/g specific surface area (SSA) and 22-42 emu/g saturation magnetization values. Establishing the UiO-66 framework via the reported semi-self-assembly resulted in roughly 70% reduction in both magnetic properties and SSA, compared with the initial MNPs building blocks and UiO-66 framework, respectively. Nonetheless, the remaining 30% of the magnetization and SSA was adequate for successful and sufficient adsorption of two different pesticides, 2,4-Dichlorophenoxyacetic acid (2,4-D) and 2,4,5-Trichlorophenoxyacetic acid (2,4,5-T), while the recovery with a commercial magnet and reuse were also found to be effective. Adsorption and kinetic studies for all three MMOFs and both pesticides were performed, and data were fitted to Langmuir-Freundlich isotherm models.

Magnetic nanoemulsions as candidates for Alzheimer's disease dual imaging theranostics.

Alzheimer's disease (AD) is the most prevalent cause of dementia linked to the accumulation of amyloid-beta (Aß) plaques-fibrils that impair cognitive functions. Magnetic nanoparticles (MNPs) are emerging as promising tools for the crusade against AD owning to appropriate biocompatibility and facile functionalization that can lead to theranostic agents. Herein, the fabrication of a multimodal (magnetic resonance imaging (MRI), fluorescence imaging, and drug carrier) magnetic nanoemulsion (MNE) is reported as an AD theranostic candidate. Initially zinc ferrite MNPs of high saturation magnetization (129 emu g-1) were synthesized through a modified microwave-assisted polyol process. Memantine (a registered AD drug) was labeled with fluorescein (Mem-Flu) and encapsulated with the MNPs in sodium dodecyl sulfate micelles to form the MNE. Small hydrodynamic size (107), high encapsulation (77.5%) and loading efficiencies (86.1%) and sufficient transverse relaxivity (48.7 mM-1 s-1) were achieved through the design while sustained release of Mem-Flu was unveiled by in zero-order, first-order, Higuchi and Korsmeyer-Peppas pharmacokinetic models. Moreover, the MNE acquired fluorescence imaging ability of Aß1-42 peptide monomers and/or plaques-fibrils via the fluorescein labeling of Memantine. A novel inorganic-organic hybrid multimodal AD theranostic candidate is presented.

Structurally characterized gallium-chrysin complexes with anticancer potential.

Chemotherapeutic metal-based compounds are effective anticancer agents; however, their cytotoxic profile and significant side effects limit their wide application. Natural products, especially flavonoids, are a prominent alternative source of anticancer agents that can be used as ligands for the generation of new bioactive complexes with metal ions of known biochemical and pharmacological activities. Herein, we present the synthesis and detailed structural and physicochemical characterizations of three novel complex assemblies of Ga(iii) with the flavonoid chrysin and the ancillary aromatic chelators 1,10-phenanthroline, 2,2'-bipyridine and imidazole. The complexes constitute the only crystallographically characterized structures having a metal core from the boron group elements and a flavonoid as the ligand. The in vitro biological evaluation of the three complexes in a series of cancer cell lines of different origin established their cytotoxicity and ROS generating potential. In particular, the Ga(iii)-chrysin-imidazole complex displayed the highest anticancer efficacy against all cancer cell lines with IC50 values in the low micromolar range (<1.18 µM), a result worth further investigation.

Structure Differentiation of Hydrophilic Brass Nanoparticles Using a Polyol Toolbox.

Nano-brasses are emerging as a new class of composition-dependent applicable materials. It remains a challenge to synthesize hydrophilic brass nanoparticles (NPs) and further exploit them for promising bio-applications. Based on red/ox potential of polyol and nitrate salts precursors, a series of hydrophilic brass formulations of different nanoarchitectures was prepared and characterized. Self-assembly synthesis was performed in the presence of triethylene glycol (TrEG) and nitrate precursors Cu(NO3)2·3H2O and Zn(NO3)2·6H2O in an autoclave system, at different temperatures, conventional or microwave-assisted heating, while a range of precursor ratios was investigated. NPs were thoroughly characterized via X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), transmition electron microscopy (TEM), Fourier-transform infrared (FTIR) spectroscopy, dynamic light scattering (DLS), and ζ-potential to determine the crystal structure, composition, morphology, size, state of polyol coating, and aqueous colloidal stability. Distinct bimetallic α-brasses and γ-brasses, α-Cu40Zn25/γ-Cu11Zn24, α-Cu63Zn37, α-Cu47Zn10/γ-Cu19Zn24, and hierarchical core/shell structures, α-Cu59Zn30@(ZnO)11, Cu35Zn16@(ZnO)49, α-Cu37Zn18@(ZnO)45, Cu@Zinc oxalate, were produced by each synthetic protocol as stoichiometric, copper-rich, and/or zinc-rich nanomaterials. TEM sizes were estimated at 20-40 nm for pure bimetallic particles and at 45-70 nm for hierarchical core/shell structures. Crystallite sizes for the bimetallic nanocrystals were found ca. 30-45 nm, while in the case of the core-shell structures, smaller values around 15-20 nm were calculated for the ZnO shells. Oxidation and/or fragmentation of TrEG was unveiled and attributed to the different fabrication routes and formation mechanisms. All NPs were hydrophilic with 20-30% w/w of polyol coating, non-ionic colloidal stabilization (-5 mV < ζ-potential < -13 mV) and relatively small hydrodynamic sizes (<250 nm). The polyol toolbox proved effective in tailoring the structure and composition of hydrophilic brass NPs while keeping the crystallite and hydrodynamic sizes fixed.

Leaf Age-Dependent Effects of Foliar-Sprayed CuZn Nanoparticles on Photosynthetic Efficiency and ROS Generation in Arabidopsis thaliana.

Young and mature leaves of Arabidopsis thaliana were exposed by foliar spray to 30 mg L-1 of CuZn nanoparticles (NPs). The NPs were synthesized by a microwave-assisted polyol process and characterized by dynamic light scattering (DLS), X-ray diffraction (XRD), and transmission electron microscopy (TEM). CuZn NPs effects in Arabidopsis leaves were evaluated by chlorophyll fluorescence imaging analysis that revealed spatiotemporal heterogeneity of the quantum efficiency of PSII photochemistry (ΦPSΙΙ) and the redox state of the plastoquinone (PQ) pool (qp), measured 30 min, 90 min, 180 min, and 240 min after spraying. Photosystem II (PSII) function in young leaves was observed to be negatively influenced, especially 30 min after spraying, at which point increased H2O2 generation was correlated to the lower oxidized state of the PQ pool.. Recovery of young leaves photosynthetic efficiency appeared only after 240 min of NPs spray when also the level of ROS accumulation was similar to control leaves. On the contrary, a beneficial effect on PSII function in mature leaves after 30 min of the CuZn NPs spray was observed, with increased ΦPSΙΙ, an increased electron transport rate (ETR), decreased singlet oxygen (1O2) formation, and H2O2 production at the same level of control leaves.An explanation for this differential response is suggested.

Interplay between Amyloid Fibrillation Delay and Degradation by Magnetic Zinc-Doped Ferrite Nanoparticles.

Amyloidosis, the aggregation of naturally soluble proteins into fibrils, is the main pathological hallmark of central nervous system (CNS) disorders, and new therapeutic approaches can be introduced through nanotechnology. Herein, magnetic nanoparticles (MNPs) are proposed to combat amyloidosis and act as CNS theranostic (therapy and diagnosis) candidates through magnetomechanical forces that can be induced under a low-frequency magnetic field. In that vein, a modified one-step microwave-assisted polyol process has been employed to synthesize hybrid organic/inorganic zinc ferrite (ZnxFe3-xO4) MNPs with different levels of zinc doping (0.30 < x < 0.6) derived from the utilized polyol. The lowest doped (x = 0.30) MNPs exhibited high magnetization (127 emu/g), high T2 imaging ability (r2 = 432 mM-1 s-1), and relatively small hydrodynamic size (180 nm), decisive characteristics to further evaluate their CNS theranostic potential. Their effect on the fibrillation/degradation was monitored in two model proteins, insulin and albumin, in the presence/absence of variant external magnetic fields (static, rotating, or alternating) via Thioflavin T (ThT) fluorescence assay and optical fluorescence microscopy. The MNPs were injected either in oligomer solution where significant fibrillation delay was observed, boosted by zinc ionic leaching of MNPs, or in already formed amyloid plaques where up to 86% amyloid degradation was recorded in the presence of magnetic fields, unveiling magnetomechanical antifibrillation properties. The alternating magnetic field (4 Hz) allows the bouncing of the MNPs into the amyloid net driven by the magnetic forces, and thus is featured as the preferred "dancing mode", which strengthens the degrading efficacy of MNPs.

Nanobrass CuZn Nanoparticles as Foliar Spray Nonphytotoxic Fungicides.

Inorganic nanoparticles (NPs) have been proposed as alternative fertilizers to suppress plant disease and increase crop yield. However, phytotoxicity of NPs remains a key factor for their massive employment in agricultural applications. In order to investigate new effective, nonphytotoxic, and inexpensive fungicides, in the present study CuZn bimetallic nanoparticles (BNPs) have been synthesized as antifungals, while assessment of photosystem II (PSII) efficiency by chlorophyll fluorescence imaging analysis is utilized as an effective and noninvasive phytotoxicity evaluation method. Thus, biocompatible coated, nonoxide contaminated CuZn BNPs of 20 nm crystallite size and 250 nm hydrodynamic diameter have been prepared by a microwave-assisted synthesis. BNPs' antifungal activity against Saccharomyces cerevisiae was found to be enhanced compared to monometallic Cu NPs. Reactive oxygen species (ROS) formation and photosystem II (PSII) functionality at low light (LL) and high light (HL) intensity were determined on tomato plants sprayed with 15 and 30 mg L-1 of BNPs for the evaluation of their phytotoxicity. Tomato leaves sprayed with 15 mg L-1 of BNPs displayed no significant difference in PSII functionality at LL, while exposure to 30 mg L-1 of BNPs for up to 90 min resulted in a reduced plastoquinone (PQ) pool that gave rise to H2O2 accumulation, initiating signaling networks and regulating acclimation responses. After 3 h of exposure to 30 mg L-1 of BNPs, PSII functionality at LL was similar to control, indicating nonphytotoxic effects. Meanwhile, exposure of tomato leaves either enhanced (15 mg L-1) or did not have any significant effect (30 mg L-1) on PSII functionality at HL, attributed to the absence of semiconducting oxide phases and photochemical toxicity-reducing modifications. The use of chlorophyll fluorescence imaging analysis is recommended as a tool to monitor NPs behavior on plants.